1. Field of the Invention
This invention relates to nonwoven surface treating articles which are useful for surface treatment, particularly polishing of various surfaces.
2. Related Art
The appearance of a surface may be indicated by "shininess", or "gloss". The "gloss" produced by buffing a surface with a surface treating article attached to a conventional rotary floor machine depends on a number of factors. Among these are the type of abrasive article employed, the nature and amount of ancillary chemical used (if any) with the article, the pressure applied to the floor, the speed of rotation of the article, the treatment time at given pressure, etc. To ensure acceptable gloss production as a result of the treatment procedure, the user tries to optimize all of these parameters. The goal is a high gloss, high durability, stain resistant floor, achieved with a minimum of labor.
Uniform, lofty, open, nonwoven three-dimensional abrasive articles are known for use in cleaning and polishing floors and other surfaces. Examples of such nonwoven surface treating articles are the nonwoven abrasive pads made according to the teachings of Hoover, et al., U.S. Pat. No. 2,958,593; McAvoy, U.S. Pat. No. 3,537,121; McAvoy, et al., U.S. Pat. No. 4,893,439; and McGurran, U.S. Pat. No. 5,030,496. Hoover et al. describe such nonwoven pads as comprising:
many interlaced randomly disposed flexible durable tough organic fibers which exhibit substantial resiliency and strength upon prolonged subjection to water and oils. Fibers of the web are firmly bonded together at points where they intersect and contact one another by globules of an organic binder, thereby forming a three-dimensionally integrated structure. Distributed within the web and firmly adhered by binder globules at variously spaced points along the fibers are abrasive particles. PA1 (a) an aqueous dispersible copolymer of an acrylate monomer and an acrylamide monomer; PA1 (b) an at least partially hydrolyzed polymer having a plurality of pendant hydroxy groups, the pendant hydroxy groups derived from a plurality of hydrolyzable pendant groups (preferably polyvinyl acetate); PA1 (c) a melamine crosslinking agent; and PA1 (d) a urea derivative. PA1 (a) an aqueous dispersible copolymer of a styrenic monomer and a diene monomer; PA1 (b) an at least partially hydrolyzed polymer having a plurality of pendant hydroxy groups, the pendant hydroxy groups derived from a plurality of hydrolyzable pendant groups (preferably polyvinyl acetate); PA1 (c) an optional melamine crosslinking agent; and PA1 (d) an optional urea derivative.
Hoover, et al., at column 2, lines 61-70, column 3, line 1.
U.S. Pat. No. 5,030,496 (McGurran) describes nonwoven fibrous surface treating articles formed of entangled synthetic fibers bonded together at points where they contact one another by a binder resin comprising plasticized vinyl resin (e.g., polyvinyl chloride or "PVC") and a condensation polymerized amine-formaldehyde derivative (e.g., melamine).
Nonwoven abrasive pads such as disclosed by McGurran, while finding wide ranging use, are disadvantageous from a production standpoint since the condensation polymerization reaction of the melamine during curing may generate volatile organic hydrocarbons (VOC). Various formaldehyde "scavengers", such as phenol, urea, dicyanodiamide, and beta-ketobutyramide, are known but each has its faults. Use of phenol is discouraged because it is a VOC. Dicyanodiamide and beta-ketobutyramide are incompatible with the melamine/PVC system because the system is organic in nature, and dicyanodiamide and beta-ketobutyramide are insoluble in the organic solvents frequently employed in production facilities used to dissolve or disperse the melamine/PVC. Urea is also insoluble in the organic solvents employed in production facilities, but can be incorporated into the melamine/PVC system in dry form; however, the resulting melamine/PVC/urea mixtures may be unstable. During the time period required for coating fibrous webs, phase separation of the urea from the melamine/PVC may occur, which may not be eliminated by decreasing the urea particle size.
Urea, however, is much more soluble in aqueous solutions than either dicyanodiamide and beta-ketobutyramide, thus requiring less energy to remove water during coating, drying, and/or coating procedures. The Merck Index, page 1553, (1989) discloses that one gram of urea will be dissolved in only one milliliter of water at room temperature, whereas one gram of dicyanodiamide requires 3 milliliters of water, and beta-ketobutyramide requires 15 milliliters of water.
Thus, it would be advantageous if binder precursor compositions could be developed for use in forming nonwoven abrasive articles having the performance characteristics described by McGurran, while avoiding the generation of VOCs and reducing energy consumption.